Abstract
The coordinated use of multiple Autonomous Underwater Vehicles can provide important advantages for oceanographic missions. One important mission application scenario can be the search of underwater plumes such as sources of freshwater of hydrotermal vents. These plumes characterize the environment by creating a gradient field of some measurable physical quantity. An innovative integrated acoustic navigation system and coordination control maneuver for a formation of 3 AUVs and I surface craft to gradient search and following missions is proposed. The specific formation geometry and topology takes in account the navigation and coordination requirements. It was designed to achieve an efficient, low cost and technically feasible solution. The system can operate in 3 modes depending on formation distances. Varying pinging rates and offsets are used to communicate parameters and mode changing. No additional underwater communication systems neither acoustic transponder deployment are needed for the vehicle coordination. This way a high degree of energy efficiency and overall mission low cost and simpler logistics is achieved. The hybrid nature of the coordinating maneuver allows the formation gradient survey and following with the efficient exploitation of the environment structuring by the phenomena to be studied. The individual control laws were designed in order to minimize the inter-vehicle communication. The coordination factors are the knowledge by the vehicles of each other behavior (since all vehicles execute the same control laws) and the detection of formation distortions. These distortions are detected by the relative navigation system. The proposed approach allows the low cost implementation of a multiple AUV coordinating control for a large range of oceanographic missions.

Abstract
In this article, we describe the analysis, design and implementation of a control architecture for a mobile platform to autonomously carry out transportation, surveillance and inspection tasks in semi-structured industrial environments. Based on a hierarchical structure composed by the Organization, Coordination and Functional levels organized linguistically and structured according to the Principle of Increasing Precision with Decreasing Intelligence, this control architecture is permits the real-time parallel execution of tasks.

Abstract
In this paper, we address the current developments of the "PISCIS" project. We focus on the experimental results from recent operational missions with an AUV in a estuarine environment. Besides describing mission planning and logistic details, we also present tools for oceanographic data processing and visualization. This will be demonstrated with some examples of collected data.

Abstract
A reliable navigation system is a key factor for the success of an operational mission with an AUV in a real scenario. In this paper, we address the main issues involved in the implementation of a long baseline (LBL) navigation system for a REMUS AUV. This system replaces both the original hardware and software of the vehicle with a simpler, faster, less expensive and more precise system, based on a Kalman filter. We also discuss the influence of transponder location in the overall performance of the LBL navigation, and present results obtained with this new system in operational missions.

Abstract
This paper describes the specification and design of a prototype of a low cost open system for the inspection of underwater structures based on a remotely operated underwater vehicle under the project IES, a 3 year long effort funded by the Portuguese R&D program Praxis XXI. Unlike commercial approaches, a modular open system characterised by the incorporation of an on-board computer allowing for advanced control capabilities is envisaged. The control console is based on a standard PC and the tether is used only for power delivery and to establish a simple communication channel. In this project, we use advanced hybrid control techniques for sophisticated semi-autonomous operation management and control. The control architecture reuses part of the one designed for the underwater vehicle Isurus operated by the Laboratory of Underwater Systems and Technologies of Porto University. The implementation is designed in order to allow for multiple sensor configurations specified as add-ins. This leads to a dynamic, scalable and flexible system that can be easily configured according to the user specifications.

Abstract
In this article, we describe the effort being carried out in the analysis, design and implementation of the control architecture for a mobile platform for autonomous transportation, surveillance and inspection in structured and semi-structured industrial environments. The control architecture is based in a hierarchical structure organized linguistically permitting the real-time parallel execution of tasks. This, architecture is composed of three levels, Organization, Coordination and Functional, structured according to the Increasing Precision with Decreasing Intelligence Principle.